Arthrofibrosis

 

This illustration shows a knee that has been cut open vertically. Normally the soft tissue folds are lubricated and allow easy bending and straightening of the knee. The kneecap (patella) will be quite mobile.

 

Inflammation in the soft tissues above and below the kneecap triggers sticky adhesions gluing up the tissue folds

 

In arthrofibrosis these adhesions mature into scar tissue, which contracts and locks up the joint

What triggers knee arthrofibrosis?

The arthrofibrotic process is triggered by inflammation most commonly affecting the fat pad behind the patellar tendon.

Then adhesions develop start to stick down the soft tissue folds of the suprapatellar pouch, posterior capsule and anterior interval underneath the tendon. This may result in flexion loss, extension loss or both. Matured scar tissue then contracts, closing the important spaces that normally allow movement, and pulling the kneecap right down (patella baja or infera), where every movement is painful.

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How common is knee arthrofibrosis?

Problems due to arthrofibrosis are uncommon but are usually consequent on significant knee surgery or injury

Significant surgery might include a multiligament reconstruction or total knee replacement, or there might have been a bad knee injury where the joint has had to be immobilised. A particular trigger is a large bleed inside the knee (haemarthrosis), with painful swelling of the joint.

Because true arthrofibrosis is not common, the importance of the symptoms may not be recognised and managed early during the physiotherapy phase. By the time the management team recognise that this process has been triggered, it may be difficult to manage.

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What symptoms suggest the onset of early arthrofibrosis?

The patient may have felt confident starting rehabilitation exercises but then may have experienced progressive problems bending the knee, and these early attempts may be excessively painful.

'Pushing through the pain' may simply make things much worse, triggering more inflammation and swelling, and further limiting range of motion. The joint may feel warm to the touch.

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Symptoms of advanced arthrofibrosis and patella baja

As the soft tissues behind and below the kneecap become involved in the scar tissue process, the kneecap may be pulled into an abnormally low position (patella baja or patella infera)

The abnormal position of the patella may result in considerable pain when trying to walk, and the knee may be most comfortable in a slightly bent position.

• Quote from peer-reviewed paper:

  "...two subtypes of arthrofibrosis occur....one involving active scar formation, and one in which inflammatory processes have resolved....each should be treated differently."

  Citation: Usher KM, Zhu S, Mavropalias G, Carrino JA, Zhao J, Xu J. Pathological mechanisms and therapeutic outlooks for arthrofibrosis. Bone Res. 2019 Mar 26;7:9. doi: 10.1038/s41413-019-0047-x. PMID: 30937213; PMCID: PMC6433953.

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Rehabilitation issues with arthrofibrosis

Early range of motion problems can be reversed with empathetic management - ideally patellar mobilisation and range of motion exercises in combination with adequate pain relief - without pushing the joint into painful inflammation that makes things worse.

Manipulation under anaesthesia may help to break adhesions before they become permanent scar tissue. Advanced arthrofibrosis with marked knee stiffness may need surgical lysis of adhesions to regain range of motion, in combination with specialist pain management and physiotherapy.

• Quote from peer-reviewed paper:

  "...to date, there is still no consensus on the best surgical procedure and rehabilitation program following MLKI [multiligament knee injury] surgery to avoid AF."

  Citation: Fahlbusch H, Krivec L, Müller S, Reiter A, Frosch KH, Krause M. Arthrofibrosis is a common but poorly defined complication in multiligament knee injuries: a systematic review. Arch Orthop Trauma Surg. 2023 Aug;143(8):5117-5132. doi: 10.1007/s00402-022-04730-9. Epub 2022 Dec 15. PMID: 36520199; PMCID: PMC10374851.

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Forum discussions about arthrofibrosis

• Soft Tissue Healing Problems - Arthrofibrosis

  Hundreds of patients' discussions about their experiences with arthrofibrosis.

• I want your arthrofibrosis success story please!!!

  A long chat about members' experiences with knee arthrofibrosis.

• Compilation of Arthrofibrosis Success Stories Timelines

  Several patients compare benchmarks for recovery from knee arthrofibrosis.

• "Arthrofibrosis Specialists"

  Patients collecting names of specialists with an interest in arthrofibrosis.

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